```
public class Solution {
public int totalHammingDistance(int[] nums) {
if (nums == null || nums.length <= 1) {
return 0;
}
int[] zeros = new int[32];
int[] ones = new int[32];
for (int num : nums) {
for (int i = 0; i < 32; i++) {
int bit = num & (1 << i);
zeros[i] += bit == 0 ? 1 : 0;
ones[i] += bit == 0 ? 0 : 1;
}
}
int totalDist = 0;
for (int i = 0; i < 32; i++) {
totalDist += zeros[i] * ones[i];
}
return totalDist;
}
}
```